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Monday, June 25

12:00 pm Registration for Pre-Conference Workshop
1:00 Welcome by Workshop Chairperson
1:55 Silicon Microstructures: A New Approach for
Molecular Biology Applications
Marie Archer, Ph.D., Post Doctoral Fellow, CBMSE, U.S.
Naval Research Laboratory
The rapid identification of harmful
organisms has become an important priority in various fields
such as clinical diagnosis and environmental surveillance.
Since each organism poses a particular genetic signature
they can be identified by their nucleic acid sequence (DNA
and/or RNA). For this purpose the nucleic acids have to be
extracted from a cell lysate using a solid phase before any
further downstream process. Recently there has been an
increasing demand for portable devices to perform this type
of assay and therefore solid phases with integration
capabilities are highly desirable. Their development
requires an interdisciplinary effort between materials
science, chemistry and molecular biology to address the
variables that affect the performance. Silicon is an ideal
candidate for this purpose due to its microfabrication
properties and the flexibility to chemically functionalize
its surface. This talk will discuss the development and
characterization of non-selective and selective solid phases
fabricated with silicon microstructures. Non-selective solid
phases are used to separate the nucleic acids (DNA and RNA)
from other components present in their medium that can
interfere with downstream processes. This separation is not
based on the nucleic acid sequence but rather in their
intrinsic electric charge which allows them to interact
electrostatically with a charged surface. Selective solid
phases are used to separate a particular nucleic acid from a
population containing various types. The separation is based
on the recognition of one nucleic acid sequence, used as a
probe, to its matching partner or complementary sequence. An
important variable in either of these two types of solid
phases is the surface area which has to be large to capture
enough quantities of the nucleic acids. The geometry, the
feature size and the surface roughness are particularly
relevant for selective solid phases. All these variables can
be controlled by fabricating solid supports through silicon
micromachining. Silicon has the additional advantage of
allowing various types of chemical modifications through
which the surface properties can be tailored for a specific
application.
2:35 Optimization and Application of FTA-Based Technology for DNA/RNA
Purification
Michael Harvey, Ph.D., Director of Development, Microarrays and Molecular Biology, Whatman
Inc.
The collection and preparation of clinical samples for molecular analysis is important for expanding applications in genetic identification, drug discovery, predictive medicine and pharmacogenomics. To simplify sample processing we have developed two chemically treated devices which are useful for dried clinical sample collection, sample archiving and, most importantly, DNA preparation for amplification. Nucleic acid preparation from samples collected on a treated matrix is simple, rapid and automatable. Blood and buccal cell samples collected on FTA®, a surfactant modified matrix, and FTA® Elute, a chaotropic salt modified matrix, can be stored for over 10 years under ambient conditions as demonstrated by STR analysis. We have demonstrated the use of DNA from these samples for genetic identification, real time PCR, DNA sequencing, and allele specific hybridization methods. Increasing demand for nucleic acids from archived samples dictates that systems and devices should be able to support whole genomic amplification. We have examined the recovery of DNA from samples archived on treated matrices and evaluated its’ suitability for whole genomic amplification. We have also measured the inter-sample variability and correlated this with nucleated cell counts, hematocrit and sample age. It is clear that blood and buccal samples dried on chemically modified matrices are stable and provide an excellent source of nucleic acids for future studies. The collection and storage of samples for RNA analysis is becoming an important application in pharmacogenomics. The stability and integrity of isolated RNA populations is essential for accurate analysis. Samples of tissue culture cells collected on FTA can be used to purify RNA populations which support RT PCR and real time analysis.
3:15 Networking Refreshment Break
3:45 Selective Enrichment and Detection of
Mycobacterial DNA in Paucibacillary Specimens
Blanca Restrepo, Ph.D., Assistant Professor, School of
Public Health Brownsville, University of Texas Health
Science Center – Houston
A major challenge for tuberculosis
control is mycobacterial detection in paucibacillary
disease, particularly in pediatric, extrapulmonary and
smear-negative pulmonary infections. We developed a simple
and efficient DNA extraction and real-time quantitative PCR
(qPCR) protocol for mycobacterial detection and
quantification in paucibacillary specimens. The method was
refined using an in vitro model mimicking blood specimens
which are characterized by the presence of numerous qPCR
inhibitors. Mycobacterial DNA detection
in blood is of interest given the high sensitivity we
previously reported using conventional PCR in blood of
patients with tuberculosis lymphadenitis. Mechanical lysis
of mycobacteria in the presence of an organic solvent
provided the highest sensitivity. Mycobacterial DNA
amplification was compromised when the human:bacterial
genome ratio was at least 190:1. Separation of the specimen
into bacterial- and host-rich fractions prior to DNA
extraction improved mycobacterial DNA detection by 30%.
Preliminary testing of our protocol in smear-negative,
culture-positive specimens (gastric and lymph node
aspirates, pleural and cerebrospinal fluid, blood) confirmed
the applicability of our technique to a range of
paucibacillary specimens for the detection, quantification
and speciation (M. tuberculosis versus M. avium) of
mycobacteria, several weeks before culture results were
available.
* Separate Registration Required
4:25 Development of Portable, Microfluidic POCT
Devices for Nucleic Acid-Based Detection
Nick Parham, Ph.D. EDM, Laval University
Nucleic acid (NA)-based technology allows the
development of tests with a controllable, yet broad range
of specificity. For example, the presence of a diverse
range of sepsis-causing microorganisms in blood can be
detected by PCR-based tests. Similarly, specific single
point-mutations (SNPs) causing genetic diseases can be
identified. For such tests, problems such as PCR
inhibitors, low target NA copy number and high background
NA concentration can often confound results. These
problems have largely been resolved for macro-scale
samples using various NA purification techniques. However,
low sensitivity remains as an important obstacle for the
detection of rare targets such as water-based pathogens or
sepsis-causing microbes. Another problem associated with
NA-based testing is that it often requires large and
expensive equipment and highly trained operators. As such,
samples are sent to specialist laboratories for
processing, which can involve significant time delays and
costs. Portable total analysis systems can facilitate
environmental monitoring and point-of-care testing.
Moreover, low-cost, disposable systems that contain stable
reagents will make these technologies available in
low-resource settings. We are developing compact disc
(CD)-based microfluidic systems for NA extraction,
purification and detection from clinical samples for
various applications in the molecular diagnosis of
infectious diseases. Our ultimate goal is to produce
low-cost, disposable microfluidic diagnostic CDs that can
be operated in a portable device for point-of-care
diagnostics.
5:05 Close of Pre-Conference Workshop
5:00-6:00 Main Conference Early Registration
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